The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the inventors hereof, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
The present disclosure is directed to methods and apparatus for directing a beam towards a receiving device (e.g., beam-forming), and more particularly to performing beam-forming in the presence of interference based on channel reciprocity.
Beam-forming is a signal processing technique used in systems for directional signal transmission or reception. The spatial selectivity may be achieved by using adaptive or fixed receive/transmit beam patterns. Beam-forming takes advantage of constructive/destructive wave interference to change the direction of the beam. As defined herein, a beam is the electromagnetic wave, carrying data to a receiver, which is formed by the (constructive/destructive) interference pattern of two or more waves transmitted by one or more antennas.
Traditionally, a receiving device receives a beam from the transmission source and computes a channel matrix for the intended channel and a channel matrix corresponding to interference caused by interference source signals and noise. In some scenarios, the receiving device computes an equivalent channel matrix that corresponds to the intended channel and the interference. The receiver in both scenarios transmits the matrices back to the transmission source for modifying the shape of the transmitted beam. Although these mechanisms for performing beam-forming are effective, these systems are inefficient in requiring the direct feedback of the channel matrices to the transmission source.